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Biomedical subjects

A Hollingworth

Publications and source records attributed to A Hollingworth.

12 recordsLinked to original sources
PubMed1999

Object identification is isolated from scene semantic constraint: evidence from object type and token discrimination.

Two models of the interaction between scene meaning and object identification were tested: the description enhancement model and the criterion modulation model. The former proposes that the early activation of a scene schema facilitates the initial perceptual analysis of schema-consistent objects, the latter that schema activation modulates the amount of information necessary to indicate the presence of an object of a particular perceptual type. In Experiment 1, we employed a forced-choice, type-discrimination paradigm. Participants were asked to determine which of two semantically consistent objects or which of two semantically inconsistent objects had appeared in a briefly presented scene. Contrary to the prediction derived from both of these models, discrimination performance was better for semantically inconsistent versus consistent objects. In Experiments 2 and 3 we introduced a forced-choice, token-discrimination paradigm to further test the description enhancement model. Contrary to the prediction of that model, discrimination performance was no better for semantically consistent versus inconsistent tokens. These results suggest that both the initial perceptual analysis of an object and the matching of an object's constructed visual description to stored descriptions are isolated from stored knowledge about real-world contingencies between scenes and objects.

Adult↗
PubMed1999

High-level scene perception.

Three areas of high-level scene perception research are reviewed. The first concerns the role of eye movements in scene perception, focusing on the influence of ongoing cognitive processing on the position and duration of fixations in a scene. The second concerns the nature of the scene representation that is retained across a saccade and other brief time intervals during ongoing scene perception. Finally, we review research on the relationship between scene and object identification, focusing particularly on whether the meaning of a scene influences the identification of constituent objects.

Eye Movements↗
PubMed1998

Does consistent scene context facilitate object perception?

The conclusion that scene knowledge interacts with object perception depends on evidence that object detection is facilitated by consistent scene context. Experiment 1 replicated the I. Biederman, R. J. Mezzanotte, and J. C. Rabinowitz (1982) object-detection paradigm. Detection performance was higher for semantically consistent versus inconsistent objects. However, when the paradigm was modified to control for response bias (Experiments 2 and 3) or when response bias was eliminated by means of a forced-choice procedure (Experiment 4), no such advantage obtained. When an additional source of biasing information was eliminated by presenting the object label after the scene (Experiments 3 and 4), there was either no effect of consistency (Experiment 4) or an inconsistent object advantage (Experiment 3). These results suggest that object perception is not facilitated by consistent scene context.

Adult↗
PubMed1997

Scintigraphic assessment of drug delivery from the Ultrahaler dry powder inhaler.

A new dry powder inhaler, the Ultrahaler, has been developed to deliver nedocromil sodium for the prophylaxis of asthma. This study was performed to compare the lung deposition of nedocromil sodium inhaled from the Ultrahaler at two different inhaled flow rates with that from a pressurised metered dose inhaler (MDI). A scintigraphic study was conducted in 12 healthy volunteers. On each study day, volunteers received a single 4.2 mg dose of nedocromil sodium from the Ultrahaler, using either an optimal (fast) inhaled flow rate or a suboptimal (slow) inhaled flow rate, or two doses of 2 mg nedocromil sodium from an MDI using an optimal (slow) inhaled flow rate. Used optimally, the Ultrahaler deposited significantly more (p < 0.05) of the metered dose in the lungs than either the Ultrahaler used suboptimally or the MDI used optimally [mean (SD) lung deposition values of 13.3 (4.8)%, 9.8 (3.5)%, and 7.5 (2.9)%, respectively]. Oropharyngeal deposition averaged over 80% of the dose for all three treatment regimens. This scintigraphic study demonstrated in vivo proof of concept for the Ultrahaler dry powder inhaler, and provided quantitative data on the relationship in lung deposition between the Ultrahaler and MDI which differed from that predicted by the in vitro fine particle fraction.

Anti-Asthmatic Agents↗
PubMed1990

The use of reservoir devices for the simultaneous delivery of two metered-dose aerosols.

Many patients benefit from using metered-dose inhalers (MDIs) with spacer or reservoir devices. Concomitant therapy with separate MDI doses of cromolyn sodium and a beta-agonist is common practice. If two puffs from each drug could be placed into a chamber, the patient could administer both medications at once, enhancing compliance. A multistage liquid impinger (a four-stage inertial impaction device incorporating an inlet bend and an absolute filter, which separates an aerosol cloud into six fractions) was used to investigate such a possibility. Cromolyn sodium and albuterol MDIs were used with an Aerochamber (Monaghan Medical Corp., Plattsburgh, N.Y.) and an Inspirease (Schering Corp., Kenilworth, N.J.). Results are reported by analyzing milligrams of cromolyn sodium per actuation retrieved. With the Aerochamber, two puffs of cromolyn sodium followed by two puffs of albuterol resulted in the total "dose to patient" being reduced by 75% (0.19 versus 0.05 mg) and the effective dose of fine particles (less than 6.5 microns) being reduced by 80% (0.13 versus 0.03 mg) compared to two puffs of cromolyn sodium alone. With the Inspirease, total dose was decreased by 80% (0.32 versus 0.06 mg), whereas the effective dose of fine particles was reduced by 60% (0.19 versus 0.05 mg) compared to one puff of cromolyn sodium alone. The use of cromolyn sodium and albuterol MDIs in a multipuff combination with the Aerochamber or the Inspirease is not recommended because this leads to a loss of the dose delivered compared to a single administration.

Aerosols↗
PubMed1989

Octadeca-9,11-dienoic acid in cervical intraepithelial neoplasia: a colposcopic study.

488 women were studied to evaluate the use of the molar ratio (%MR) of octadeca-9,11-dienoic acid (18:2(9, 11] to linoleic acid (18:2(9, 12] as a new screening method for cervical cancer and pre-cancer. A combination of Papanicolaou cytology, colposcopy and %MR 18:2(9, 11)/18:2(9, 12) were employed. 86 women (17.6%) were found to have histologically proven cervical intraepithelial neoplasia (CIN). The %MR was obtained in 452 cases (92%). There was no significant difference in %MR in cervical cell scrapes from women with or without CIN. The %MR of cervical scrapes in some women with anaerobic vaginosis was significantly elevated suggesting bacterial generation of 18:2(9, 11). The %MR of 18:2(9, 11)/18:2(9, 12) is unsuitable for the diagnosis of cervical intraepithelial neoplasia.

Adult↗
PubMed1989

An explanation for the problem of false-negative cervical smears.

False-negative cervical cytology due to sampling error is a well-recognized problem. Forty-seven women with histologically proven cervical intraepithelial neoplasia (CIN) were studied. All had two cervical smears performed at a mean interval of 3 months. At the time of the second smear, cervicography, colposcopy and biopsy were performed. The area of acetowhite cervical lesions and of the total visible atypical transformation zone (ATZ) were measured from the cervical photographs. The 17 women in whom one or both smears showed no dyskaryosis were found to have a significantly smaller proportion of their ATZ affected by CIN. It is suggested that this finding can account for the sampling error which causes false-negative cervical cytology. New screening techniques, such as cervicography, may offer a method of detecting and assessing these relatively smaller cervical lesions.

Biopsy↗
PubMed1989

Cytological status and lesion size: a further dimension in cervical intraepithelial neoplasia.

Quantitative histological study of 84 laser cone biopsies showed a highly significant correlation between the grade of a cervical smear and the size of the lesion for all grades of cervical intraepithelial neoplasia (CIN) (CIN I P = 0.004; CIN II P = 0.0001; CIN III P = 0.003; total CIN P less than 0.0001); 10 of 34 (29%) of women with CIN III and mild dyskaryosis or less had significantly smaller lesions than 23 of 36 (63%) of women with CIN III and moderate or severe dyskaryosis. Repeat cytology identified as severe dyskaryosis all those with large CIN III lesions. Lesion size has been neglected in studies of the natural history of CIN and in the assessment of cytological screening, but offers an explanation for the apparent discrepancies between cytological, colposcopic and histological assessment of progression of CIN.

Biopsy↗
PubMed1989

Possible cofactors in the etiology of cervical intraepithelial neoplasia. An immunopathologic study.

Previous work in our department demonstrated a reduction in the numbers of Langerhans' cells in cervical epithelium showing histologic changes of human papillomavirus (HPV) infection and cervical intraepithelial neoplasia (CIN). In conjunction with a localized reversal of the T4:T8 ratio of T-lymphocytes, that finding provides evidence of the association of epithelial immunosuppression with both HPV infection and CIN. To investigate whether that phenomenon occurs primarily because of HPV alone or might be caused by a cofactor (e.g., cigarette smoking, oral contraceptive use, chlamydial infection), we performed a study of the effect of those cofactors on the immune defenses of the cervical epithelium. In a study of Langerhans' cells we showed that infection with HPV type 16 and current cigarette smoking both exert effects that cause a reduction in those cells. That diminution of the major antigen-presenting cells in cervical epithelium may constitute a mechanism that explains the observed role of those agents in the etiology of cervical neoplasia.

Antigens, CD1↗
PubMed1982

Comparison of bupivacaine and prilocaine used in Bier block--a double blind trial.

The value of Bier blocks for the manipulation of fractures and for operations on the upper limb is well recognized. Two anaesthetic agents, bupivacaine and prilocaine, are widely used for this purpose. A prospective double blind trial of 200 patients has been carried out to compare the efficacy of each drug and the incidence of side effects. The study shows that bupivacaine was associated with a greater number of successful fracture reductions than prilocaine with little difference in their analgesic effects, but this was balanced by more minor side effects with bupivacaine. There was little difference in the time from injection to analgesia in the two groups. All intravenous regional analgesia procedures were carried out by junior orthopaedic or accident and emergency doctors. The overall success rate for analgesia was 91 per cent but marked cuff discomfort occurred in 9 per cent of patients. There was a clear association between failure of analgesia and two of the doctors carrying out the procedure.

Adolescent↗